(a) Field of the Invention
The present invention relates to an air guide nozzle of a spray gun, and more particularly to one provided with dual pressure reduction mechanism to delivery stabilized airflow.
(b) Description of the Prior Art
The structure of air outlet found with the spray guns generally available in the market as illustrated in FIG. 4 features a nozzle (A) that is provided at the front end of a spray gun (C) combined with a retainer ring (B) and a nozzle lid (D). An inclined paint inlet (C1) is provided at the top of the spray gun(C) and multiple air outlets (C2) are provided on the surface of the front end. Wherein, a nozzle base (A1) is formed at the front end of the nozzle (A). Multiple bores (A11) are axially provided along the nozzle (A) on the nozzle base (A1) while a reduction stopper (A12) is formed on the peripheral in relation to those bores (A11), and a threaded section (A2) is formed at the rear section of the nozzle (A). Furthermore, an inner passage (B1) is formed in the inner circumference of the retainer ring (B) with a gap (B11) formed appropriately to the passage (B1). Upon assembling, as illustrated in FIG. 5, the retainer ring (B) is flush provided at the bottom of the front end of the spray gun (C). The gap (B11) of the retainer ring (B) is just located opposite to the air outlet (C2) of the spray gun (C). Then the threaded section (A2) of the end of the nozzle (A) is axially engaged to the front end of the spray gun (C), and axially extends into the retainer ring (B) to provide a proper spacing between the nozzle (A) and the inner circumference of the retainer ring (B). Finally, the nozzle lid (D) is aligned and screwed in relation to the front end of the spray gun (C) so that both of the nozzle (A) and the retainer ring (B) are inserted in the nozzle lid (D). Upon spraying, the air is delivered in two channels. One channel allows the air to be released through the bores (A11) provided at the nozzle base (A1) of the nozzle (A) and the other channel permits the air to flow into and fill the space provided by the inner circumference for pressure reduction. The pressure-reduced air then joins that airflow delivered from the spacing between the nozzle (A) and the retainer ring (B) with its pressure reduced by impacting against the stopper (A12). The aggregated airflow in the space provided in the spray gun lid (D) is stabilized with its pressure for spreading.
However, there are defectives found with the prior art of the spray gun nozzle:
1. Both of the nozzle and the retainer ring are two independent and separated members and each requires respective manufacturing process. To demand the perfect assembly between said two members, it requires a strict calculation of the combination allowance between both members to avail the desired spacing between the nozzle and the retainer ring, so that the output of airflow may be at the level as expected. However, it is a canny sense to those who are familiar with the practice that the error must fall within a pre-determined range for any part or component that requires to be combined with another member. The manufacturing cost and the process for such part or component will be higher and more difficult than those found with the general member. Therefore, the prior art is not cost efficiency in terms of manufacturing.
2. Furthermore, upon assembling the prior art, the retainer ring must be first made flush behind the front end of the spray gun to allow the nozzle to be provided onto the spray gun before locking up the spray gun, lid. onto the front end of the spray gun. The assembly is complicated, and thus is very time consuming.
The primary purpose of the present invention is to provide a spray gun air guide nozzle structure with dual pressure reduction mechanism to provide pressure stabilized delivery of airflow. In order to achieve a more stabilized air output for the well distributed atomized paint, the nozzle is made with an axial passage with a disk shape stern extended from the front end of the passage. The middle section of the nozzle is formed a base provided with multiple bores while another stopper with multiple air vents extends from the outer circumference of the nozzle base to compromise those air vents for forming a buffer on the edge of the nozzle base. The rear end of the nozzle is provided with a threaded section to fasten it to the spray gun. The air delivered through the air vents on the stopper at the circumference of the nozzle base by the spray gun is reduced with its pressure by impacting upon the buffer, and that air delivered through the bores on the nozzle base has also its pressure reduced by hitting against the stopper provided on the circumference at the tip of the nozzle. The air having its pressure reduced then leaves an air hole provided at the spray gun lid to become a pressure stabilized airflow to spray the paint delivered through the passage of the nozzle.